code: def sub_cluster(
      cid_tid_dict,
      scene_cluster,
      use_ff=True,
      use_rerank=True,
      use_camera=False,
      use_st_filter=False,
  ):
      """
      cid_tid_dict: all camera_id and track_id
      scene_cluster: like [41, 42, 43, 44, 45, 46] in AIC21 MTMCT S06 test videos
      """
      assert (
          len(scene_cluster) != 0
      ), "Error: scene_cluster length equals 0"
      cid_tids = sorted(
          [
              key
              for key in cid_tid_dict.keys()
              if key[0] in scene_cluster
          ]
      )
      if use_camera:
          clu = get_labels_with_camera(
              cid_tid_dict,
              cid_tids,
              use_ff=use_ff,
              use_rerank=use_rerank,
              use_st_filter=use_st_filter,
          )
      else:
          clu = get_labels(
              cid_tid_dict,
              cid_tids,
              use_ff=use_ff,
              use_rerank=use_rerank,
              use_st_filter=use_st_filter,
          )
      new_clu = list()
      for c_list in clu:
          if len(c_list) <= 1:
              continue
          cam_list = [cid_tids[c][0] for c in c_list]
          if len(cam_list) != len(set(cam_list)):
              continue
          new_clu.append([cid_tids[c] for c in c_list])
      all_clu = new_clu
      cid_tid_label = dict()
      for i, c_list in enumerate(all_clu):
          for c in c_list:
              cid_tid_label[c] = i + 1
      return cid_tid_label
  
file_path: PaddleDetection/deploy/pptracking/python/mot/mtmct/postprocess.py
imports: import os
  import re
  import cv2
  from tqdm import tqdm
  import numpy
  from functools import reduce
  from .utils import parse_pt_gt, parse_pt, compare_dataframes_mtmc
  from .utils import get_labels, getData, gen_new_mot
  from .camera_utils import get_labels_with_camera
  from .zone import Zone
  from ..visualize import plot_tracking
label_desc: Use image node_id 2 for calling a global function with example usage: sub_cluster(cid_tid_dict, scene_cluster, use_ff, use_rerank, use_camera, use_st_filter) and returns: cid_tid_label